@Article{BABARCollaborationdelAmoSanchez_etal2011, author="BABAR Collaboration (del Amo Sanchez, P. et al and Lopez-March, N. and Martinez-Vidal, F. and Oyanguren, A.", title="Search for Production of Invisible Final States in Single-Photon Decays of Gamma(1S)", journal="Physical Review Letters", year="2011", publisher="Amer Physical Soc", volume="107", number="2", pages="021804--7pp", abstract="We search for single-photon decays of the Gamma(1S) resonance, Gamma -> gamma + invisible, where the invisible state is either a particle of definite mass, such as a light Higgs boson A(0), or a pair of dark matter particles, chi(chi) over bar. Both A(0) and chi are assumed to have zero spin. We tag Gamma(1S) decays with a dipion transition Gamma(1S) -> pi(+)pi(-)Y(1S) and look for events with a single energetic photon and significant missing energy. We find no evidence for such processes in the mass range m(A0) <= 9.2 GeV and m(chi) <= 4.5 GeV in the sample of 98 x 10(6) Gamma(2S) decays collected with the BABAR detector and set stringent limits on new physics models that contain light dark matter states.", optnote="WOS:000292516600008", optnote="exported from refbase (https://references.ific.uv.es/refbase/show.php?record=691), last updated on Tue, 09 Aug 2011 10:13:23 +0000", issn="0031-9007", doi="10.1103/PhysRevLett.107.021804", opturl="http://arxiv.org/abs/arXiv:1007.4646", opturl="https://doi.org/10.1103/PhysRevLett.107.021804", archivePrefix="arXiv", eprint="arXiv:1007.4646", language="English" }